Sakamoto Waka, Azegami Nanako, Konuma Tsuyoshi, Akashi Satoko
Anal Chem. 2021 May 4;93(17):6583-6588. doi: 10.1021/acs.analchem.1c00588. Epub 2021 Apr 19.
Native mass spectrometry (MS) enables the determination of the molecular mass of protein complexes. Generally, samples for native MS are isolated, purified, and prepared in volatile solutions. However, to understand the function of proteins in living cells, it is essential to characterize the protein complex as is, without isolation/purification of the protein, using the smallest possible amount of the sample. In the present study, we modified the "live single-cell MS" method, which has mainly been used in metabolomics, and applied it to observe hemoglobin directly sampled from human erythrocytes. By optimizing the experimental methods and conditions, we obtained native mass spectra of hemoglobin using only a single erythrocyte, which was directly sampled into a nanoelectrospray ionization emitter using a micromanipulator and microinjector system. That is, our method enables the analysis of ∼0.45 fmol of hemoglobin directly sampled from an erythrocyte. To our knowledge, this is the first report of native MS for endogenous proteins using a single intact human cell.
原生质谱（MS）能够测定蛋白质复合物的分子量。一般来说，用于原生质谱的样品需在挥发性溶液中进行分离、纯化和制备。然而，为了了解蛋白质在活细胞中的功能，至关重要的是在不分离/纯化蛋白质的情况下，尽可能少地使用样品来直接表征蛋白质复合物。在本研究中，我们改进了主要用于代谢组学的“活单细胞质谱”方法，并将其应用于观察直接从人类红细胞中采样的血红蛋白。通过优化实验方法和条件，我们仅使用单个红细胞就获得了血红蛋白的原生质谱，该红细胞使用微操纵器和微注射器系统直接采样到纳米电喷雾电离发射器中。也就是说，我们的方法能够分析直接从红细胞中采样的约0.45飞摩尔的血红蛋白。据我们所知，这是首次使用单个完整人类细胞对内源蛋白质进行原生质谱分析的报告。
